There's been a lot of those, though I think the majority have been deleted by now. Either way, it'd be helpful if you were more specific.

I think the creepypasta was about an easter bunny like creature SA'ing an 18 year old girl who had a boyfriend

Just google "most popular female creepypasta characters"

I'm searching for a whole creepypasta I read when I was younger, not a creepypasta character

Tbh even that description isn't narrowing it down that much. How long ago did you read it, exactly? We pruned a lot of the NSFW category in the mid-to-late 2010s.

Around 2013 or 2014

It's probably long gone in that case lol

But mostly around late 2013

But, that creepypasta that I've read when I was younger was mostly traumatizing because of this one scene where the easter bunny like creature was raping the 18 year old girl...

That's mostly why I'm suspecting it's been deleted at this point. Drawn out rape/SA scenes were (and still are) against the Wikia/FANDOM ToU, but that wasn't as heavily enforced in this wiki's early days.